Apparatus for forming spiral tubing from a ribbon of thin material



CRAWFORD APPARATUS FOR FORMING SPIRAL TUBING March 14, 1967 T. J.

FROM A RIBBON OF THIN MATERIAL 5 Sheets-Sheet 1 Filed May 11, 1964INVENTOR. Thomas J. Crawford A T TORNE V T. J. CRAWFORD APPARATUS FORFORMING SPIRAL TUBING March 14, 1967 FROM A RIBBON OF THIN MATERIAL 5Sheets-Sheet 2 Filed May 11, 1964 &m

d m Am a w n O a T r. m C mm a W 1 2w 1 m9 5% v9 w& m w m 3 O i In 1- aTI m MQ ATTORNEY 5 Sheets-Sheet 5 INVENTOR. Thomas J. Crawford ATTORNEYT. J. CRAWFORD APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON OF THINMATERIAL m h .l. S m T a 4 ,%\W/ b. m9

IIA IIIlllllltlll'lllllllllllflulhVFY TIIII'III March 1967 T. J.CRAWFORD 3,309,003

APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON OF THIN MATERIAL 5Sheets-$heet 4 Filed May 11, 1964 INVENTOR.

Thomas J Crawford ATTORNEY March 14, 1967 "r. J CRAWFORD 3,309,003

APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON 0F THIN MATERIAL 5Sheets$heet 5 Filed May 11, 1964 INVENTOR. Thomas J Crawford BY ATTORNEY3,399,003 APPARATUS FOR FORMHNG SPIRAL TUBING v FROM A RIBBON 9F THINMATERIAL Thomas J. Crawford, Bainbridge, Ga, assignor to Universal MetalHose Company, Chicago, 111., a corporation of Delaware I Filed May 11,1964, Ser. No. 366,442 17 @laims. (Cl. 228-15) This invention relatesgenerally to apparatus for making spiral tubing from a strip or ribbonof sheet material by forming it into a helix and securing the meetingedges of successive wraps of the helix.

The invention relates particularly to apparatus for making thin Walltubing, in a choice of diameters, from strip or ribbon selected from avariety of materials, widths and thicknesses.

While this invention is broadly applicable to making tubing from metals,and non-metallic materials such as plastics, it relates especially toapparatus for making tubing from a strip or ribbon of very thin metalsuch as copper or steel in the order of .Olf thick, by forming theribbon into a helix and securing the meeting edges of successive wrapsas by welding.

A primary object of the present invention is the provision ofspiral-tubing-formingapparatus having a pair of tubular,counter-rotatable, axially-aligned mandrels, means for guiding andcontinuously feeding a ribbon of material diagonally onto and around themandrels in succession, and means intermediate the ends of the mandrelsfor securing as by welding the meeting edges of successive wraps ofribbon to produce spiral tubing.

A feature of the present invention is that the first mandrel onto whichthe ribbon is fed rotates in a direction opposite the movement of theribbon to thereby stabilize progress of the ribbon wraps in a directionlengthwise of the mandrels,

Another feature is that the tubing, after being welded, is carried alongthe second mandrel which rotates in the direction which the finishedtubing rot-ates, the second mandrel having a longer portion infrictional engagement with the ribbon wraps than the first mandrel.

An object of this invention is the provision of an end less, flexible,friction-belt drive for feeding the ribbon along the guide means andthen successively about first and second counter-rotating mandrels. 7

Another object is the provision of control means for varying therelative speeds of the counterrotating mandrels to adjust the pressurebetween meeting edges of successive ribbon wraps 'at the point ofwelding. -This enables a very precise control over the density andhomogeneity of the metal along the welded edges.

Another object is to weld or otherwise secure the meeting edges ofsuccessive wraps of the ribbon at a location between the mandrels, forbest adjustment ofthe pressure between the edges at the point ofwelding.

Another object is to provide a pair of'axially aligned, counter-rotatingmandrels with space between them and .to perform the welding operationover that space. Another object, ancillary to this, is to wrap theribbon substantially completely about said space to make it prac- UnitedStates Patent Ofiice ti-cally gas tight and to introduce an inert gasthrough one of the mandrels into the space to facilitate an electricfusion welding operation on the meeting edges.

Another object is to mount the mandrels, respectively, on a pair oftubular, concentric drive shafts which are journaled for rotationrelative to a support frame andto one another and to provide means forcooling at least the second mandrel through a cooling medium path whichincludes a central cooling tube located within the inner one of thedrive shafts.

Another object is a mount the ribbon guide meanson Patented Mar. 14,1967 an auxiliary frame which is pivotable about .an axis extending in adirection to substantially intersect the welding area adjacent themandrels; thus, the guide means can be pivotally adjusted about thataxis to preselect the angle of approach of the ribbon toward themandrels to enable the use of different width ribbons anddifferent-diameter mandrels.

Anotherobject is to provide ribbon feeding means in the form of atensioned, endless, flexible, friction belt and means for driving it inan orbital path along the ribbon guide means and following at least thefirst ribbon wrap about the mandrels for continuously feeding themeeting edges of successive wraps past the welding operation while theyare held in perfect cylindrical alignment with one another against theouter surfaces of the mandrels.

Other objects and advantages will be apparent from the followingdescription taken in connection with the drawings in which:

FIGURE 1 is a front elevation of one preferred form of spinal tubemaking machine made in accordance with the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a partial, cross-sectional view of FIG. 1 showing the doublemandrel construction. about which the spiral wrapped tube is form-ed;

FIG. 4 is an enlarged cross-sectional view of the lefthand end portionof FIG. 3 showing additional details, particularly the water and gasconnections and the mandrel drive pulleys;

FIG. 5 is an enlarged cross-sectional view of the righthand end portionof FIG. 3 showing the area between the two mandrels where the metalstrip is welded into tub- FIG. 6 is a fragmentary enlarged view of FIG.5 showing in more detail the area between the mandrels and the paths ofgas and cooling water;

FIG. 7 is a transverse cross-sectional view of the machine, taken at thewelding position as indicated by line 7-7 in FIG. 5;

FIGS. 8 and 9 are transverse cross-sectional views of FIG. 6 taken alongthe lines 8-8 and 9-9 respectively;

FIG. 10 is a fragmentary perspective view of the welding area at themandrel showing particularly the guide and hold-down arrangement for theincoming met'al strip;

FIG. 11 is a partial plan viewof FIG. 1-0 showing the welding juncturewhere the incoming metal strip becomes spiral-weldedtubing;.and f FIG.12- isafragmentary view similar .to..FIG. ll showing schematically analternate form of welding.- The same parts arereferred to by the samereference numbers throughout the figures of the drawings.

Referring now particularly to FIG. 1, of the embodiment of the inventionshown. in .the drawings, there -i s a main, mandrel-supporting frame 21vwhich'includes' a base 22, and an upright end section 23 with a gusset24 which supports a split tubular. mandrel enclosure 26. At the oppositeor exit end of the base is another upright supporting section 27.

An auxiliary. frame 28 is mounted on the main frame for pivotal movementabout an upright axisindicated A-A in FIG. 1 and FIG. 7.. The auxiliaryframe is made with a turntable bottom plate 29 which rests upon the base22 and any suitable means, for example bolt means 31, may be employed tohold the auxiliary frame in a preselected adjusted position.

As will be described in more detail, the auxiliary frame 28 carries theribbon storage reel, the guide for directing the ribbon diagonally ontothe mandrels, and the positive feed means for moving the'ribbon over theguide onto the mandrel means.

The mandrel means comprising first and second countor-rotating mandrels,and the supports and driving mechanisms for them, will now be described.

As best shown in FIG. 3, the tubular mandrel encl-osure 26 supported onthe main frame is split lengthwise along the top and is formed with apair of spaced, longitudinal, upstanding flanges 32, 32. These are drawntogether by bolts 33 to grip a mandrel support tube 34 and hold itfirmlyin place.

Outer and inner drive shafts 36 and 37 respectively for the first andsecond mandrels will now be described. Refer to FIGS. 3 and 4. The outerdrive shaft 36 is a tube journaled by means of bearings 41, 42 withinthe mandrel support tube 34. That shaft 36 is held against end play by acollar portion 43 and a threaded l-ock nut 44, at opposite ends. At themandrel end, the outer. drive 36 terminates in an outwardly flared bore46 within which is held a tapered end portion 47 of the first mandrel 38as by a coupling ring 48, the latter being threadedly engaged with theend of the outer drive shaft and in abutment with a collar 49 formed onthe outside of the first mandrel. 7

At its left-hand end in FIGS. 3 and 4, the outer drive shaft 36 has anextension 51 to which a. pulley 52 is affixed by a key 53 and set screw55.

The inner drive shaft 37, which carries the second mandrel 39, islikewise in the form of a hollow tube and is journaled for rotationrelative to the outer drive shaft 36 by bearings 54, 56 and 57 (seeFIGS. 4 and As shown in FIG. 5, bearings 57 are preferably long, thin,needle bearings which are preferred for the restricted space availablethere.

As best shown in FIG. 4, the inner drive shaft 37 is provided with apower driving sleeve 58 held by a pressed or snug fit on the turnedsections 59 and 61 of the inner drive shaft. provided at the inner endof the driving sleeve 58 to back up the bearing 56. A tubular spacer 64holds the bearings 54 and 56 properly spaced apart, the twobeing heldwithin a bearing retainer sleeve 66. This latter sleeve is provided withan outer knurled flange 67 and is threadedly assembled within the bore68 of the outer drive shaft 36. A lock nut 69 holds the sleeve 66- inproper longitudinal position. A short bearing retainer sleeve 71 holdsthe bearing 54 in place and is itself threadedly engaged within theknurled flange 67.

An outer extension 72 of the power driving sleeve 58 is provided with apulley 73 held in place by a key 74 and set screw 75. The sleeveextension 72 is, in turn, keyed to the inner drive shaft 37 as at 76'andlock nuts 77, 78 are provided to provide end support.

A multiple rota-table coupling, generally designated 79, and best shownat the left-hand portion of FIG. 4, provides entry and exit for coolingliquid and entry for inert gas such as argon which may be used in thewelding operation to be described.

The coupling 79 comprises, in this case, a series of interlockingsections 81, 82, 83, 84, 86 and 87 held together by a series of longbolts 88 (only one shown, in FIG. 4). All the sections are boredinternally, as shown, to receive the extreme left end portion of theinner drive shaft 37.

Sections 81, 83 and 86, respectively, have transverse ports fitted withthe following: a cooling water intake pipe 89; a water outlet pipe 91;and a gas inlet pipe 92.

The outer end portion of the inner drive shaft 37, within the coupling79, is counter-bored to receive a manifold tube 93 which directs thefluids into the proper passages. As shown in FIG. 4, the right-hand endportion of the manifold tube 93 has a counter bore into which an outerfluid tube 94 is assembled as for instance by a press fit andsilversolder. At the left-hand portion of the manifold tube 93, there is asmaller counter bore within which an inner fluid tube 96 is similarlyassembled. At the extreme left-hand end of the manifold tube 93, asseen-in FIG. 4, there is a bushing 95'which'sup- A threaded nut 62 and aspacer 63 are ports the end of the inner fluid tube 96. If preferred,instead of the press fit and silver solder as above mentioned, the tubes94 and 96 may simply be pressed snugly into place and maintained fluidtight by O-rings 97 and 98. Likewise, the manifold tube 93 may bemaintained fluid tight within the drive shaft counter bore by O-rings99.

Water enters the pipe 89, passes into the cup-shaped end space 101,around the end of inner drive shaft 37 and manifold tube 93 and passesthrough the bushing into the inner fluid tube 96. The water passes allthe way to the end of the inner tube where it exits as shown in FIG. 5and, as will be described later, returns in the annular space betweentubes 94 and 96.

When return water emerges from said annular space, as stated above, itpasses into the counter bore '102, through openings 1G3 and 104 in themanifold and drive shaft and thence out of the water exit pipe 91.

Gas, entering the pipe 92, passes into the annular space 106, thencethrough opening 197, into counter bore 108, and then flows to the right,toward the welding operation, in the annular space 105 between theoutside of tube 94 and the inside surface 1090f the inner drive shaft37. Gaskets 111 provide fluid tight seals between the adjacent sectionsof the coupling 79 and prevent leakage and short-circuiting of the Waterand gas.

The coupling 79 does not itself rotate. It is The inner drive shaft 37rotates Within it.

The outer ends of the drive shafts 36 and 37 and the mandrels andassociated parts will now be described in connection with FIGS. 5through 9.

The actual working surfaces of the first and second mandrels arecylindrical, are substantially the same diameter, and are indicated bythe reference characters 38a and 39a. At its extreme outer end, thefirst mandrel 38 is counter bored to receive a seal 112 and a retainer113 (FIG. 6).

The second mandrel 39 comprises in the present case two pieces numbered114 and 116 held together by set screw means 117. At the outer end, themandrel section 114 is keyed to the inner shaft 37 as shown at 118 and apair of end lock nuts 119, 121 hold the assembly together. The end ofthe inner drive shaft is closed by a threaded pipe plug 122.

As shown in FIG. 6, the inner end portions of the inner and outer fluidtubes 96 and 94 are maintained concentric with the inner drive shaft 37by means of collars 123 and 124 respectively. O ring seals are'providedin the peripheries of these collars, as shown in FIG. 6.

Cooling water, flowing leftwise along the outside' of tube 96, withinthe second mandrel 39, follows this path: it exits through a port 126,into an annular chamber 127 which is adjacent and within the weldingspace 128 on the outside of the second mandrel. Thence around thechamber 127, inward through port 129 and leftwise toward the wateroutlet pipe 91 through the annular space between concentric tubes 94 and96.

As shown in FIGS. 6 and 7, the inert gas flow through the annularchamber along the outside of tube 94 exits through a port 131, into anannular chamber 132, through radial ports 133 into the welding space128.

It will be understood that, for different diameter spiral tubing, themandrels will be removed and replaced with different diameter mandrels.

The mandrels are driven in opposite directions relative to one anotherand the speed of either is controllable relative to the other by theportion of the apparatus shown in FIGS. 1, 2, 3 and 4. Pulley 52, whichis for the outer drive shaft 36 and the first mandrel 38, is driven by amotor 136, variable speed transmission 137 having a speed control handle138, belt 139, angle drive 141, and belt 142. By a similar arrangement,pulley 73 for the inner drive shaft 37 and the second mandrel 39 isdriven by a motor 143, variable speed transmission 144 controlled byhandle 146,'belt 147, angle drive 148,

stationary.

. tubing to be produced. The

and belt 149. The mandrels are rotatably driven in opposite-directionsas shown by" the arrows in FIG. 11.

As indicated in FIG. 1 the auxiliary frame 28 is pivoted" relative tothe base 22 about an: upright axis AA. Above the plate 29, the auxiliaryframe is formed with an angled support plate 151 with a base plate 152atop it. For convenience in setting the machine up for a job, plate 152'may be made-adjustable relative to plate 151 in any of a variety of wayswhich a mechanic skilled in this art will recognize as convenient, Onthe plate 152 is an upright wall 153 supported by' a gusset 154, uppersidewalls 1'56- and 157, and a top, box-end wall 158 to give theauxiliary frame strength and rigidity. The lower part of sidewall156has' a curved fore portion 159 which curves around under a ribbonstorage reel now to be described.

A strip or ribbon 161' of raw material such as copper or stainless steelis supplied to the. machine in convenient coil form 160. The center ofthe coil will he slid over the four posts or rods 162. of a .reel 165and against a flat annular sidewall 163. By expanding linkage means 170,the hand wheel 164 may be turned to adjust the effective diameter of.the four posts 162", to move them in or out; to fit the inside of a widevariety of coils; It will be observed from FIG. 1 that the auxiliaryframe above the plates 151, 152 is tilted at a slight angle with respectto the vertical. This enables the ribbon reel 160 to remain stablyagainst the single reel sidewall 163- without requiring one on each sideof the reel. It also enables the rib-bon to be fed off. the reel,without. twisting it out of. the plate of the reel, into perfectalignment. with the guide. means just prior to the mandrels, as willhereinafter be explained.

The reel 165 ismounted. on a wall 166- of the auxiliary frame, having a.projecting hub 167 on which. is mounted a pulley 168 carrying a shaft169 through the wall 166 and into driving engagement with the reel.Amotor 171, angle drive 172, and belt 173 drive the reel automaticallyas will next be described.

The ribbon 161 is automatically maintained in a preferabl-y long loopextending toward the floor, by the following control apparatus. A roller176 is lightly engaged within the. ribbon. loop and is mounted on theend of an arm 177 of a switch 178. Whenever theloop shortens, by feedonto the mandrels,v sufficiently to raise the switch arm 177apredetermined amount, it closes a circuit (not shown) which starts motor171. This rotates the reel to drive off a predetermined amount of theribbon 161 to a point where switch. lever 177 drops-and stops the motor171.

The guide means for guiding the ribbon or strip 161 onto the mandrelswill now be described. At this point, attention is directed tothe factvthat the strip may be extremely thin, almost flimsy, and no kind ofguide forceably abutting the edges, as is commonly used with thickerstrip, will be effective. It is essential that the strip-arrive at thewelding point on the mandrels with the edges perfectly smooth andunbroken. As. above described, the strip 161 is trained in a long gentleloop, inv some cases almost all the way to the floor, and then loopedback, up, overa roller 174. Note that. this roller is considerably widerthan necessary for the particular strip shown in FIG. 1. The reason forthis is that the roller can support stripsof different widths dependingon the size of present machine is quite versatile in this respect.

Beyond the roller 174, the strip. passes up a flat guide plate 179,diagonally toward the mandrels; A. pair of upstanding side plates 181are provided on both sides of the ribbon and the spacing between theseside plates is adjustable for dilferentwidths of ribbon. Referring nowto FIG. 11, the ribbon 161 is fed forward, diagonally, onto the firstmandrel, in a direction which is counter to the rotation. of the firstmandrel. The ribbon makes a. first complete wrap about the first mandreland meets its second wrap substantially at a point 182 which is over thewelding space 128 previously described. At this point, as shown in FIGS.7 and 10, there is an electric fusion welding electrode 183 whichcontinuously welds the meeting edges of successive wraps to producespiral welded tubing 184 on the second mandrel. An argon-shielded,tungsten-electrode, arc-welding procedure is employed in this embodimentof the invention.

The guide plate 1'79 approaches the first mandrel diagonally, at anangle of approach designated A/F in FIG. 11. In addition, by reason ofthe angled mounting of theplates 151, 152 (FIG. 1), the guide plate 179is canted, that is, tilted slightly clockwise so that its right edgeportion is lower than its left edge portion. This guides the ribbon 161into tangency with the surface of the first mandrel along a line whichis indicated as a broken line TT in FIG. 11. Note that this line oft'angency is non-parallel to the axis ofthe mandrels and the right-handedge of the entering strip 161 is somewhat in advance of the weldingpoint 182. In other words, at theline TT, the strip is on thecylindrical surfaces of the mandrels, ready for a perfect weld. It willalso be observed in FIG. 11 that the point of tangency of the right-handedge of the approachingstrip 161 is somewhat in advance of the weldingspace 128. This provides a complete wrap, forming a substantiallygastightouter enclosure for the welding space 128.

When fusion welding the circumferential or helical seam on the rotatingassembly, it is important to weld ahead of the top center to permit themolten pool of metal to freeze before it is far enough over the hill toallow the molten metal to run ahead of its corresponding base metal withresulting loss of control of the weld contour. An important function ofthe angled approach plate 179 and sub-base 2'9, 151 is to bring theribbon uphill to the mandrels, bring the edges together ahead of topcenter, and allow the welding arc to be usedahead of top center. Line TTis slightly skewed (FIG. 11) and entirely ahead of top center position.The skew allows a slight excess of metal to form a slight weld bead orreinforcement; it is not significantly depended upon for weld pressure.Pressure is supplied by the contra-rotating mandrels and the resultantfrictional force vectors.

A feature of this machine which facilitates handling extremely thinmaterial is that the ribbon coil is in the same upright plane (which isangled, as shown in FIG. 1) as the guide 179. Furthermore, the upperguide surface. offthe latter is parallel to the axis of the reel. Bythis arrangement, the ribbon 161 is fed from the reel, without warpingor twisting, onto the guide 179. This is important in handling fragilemetallic-ribbon for the present purpose.

The: length of the second mandrel 139 in frictional contact with theribbon wraps is greater than that of the first mandrel. This biases thefinished spiral welded tubing 18.4; to rotate in the direction of thesecond mandrel as the. tubing'is being produced and fed off the machine.

Power means for feeding the ribbon 161 onto the mandrels comprisesendless belt means which in the present case takes the form of a pair offlexible rubber belts 186, 187,.driven by a motor 188. This will now bedescribed.

The motor 188 (FIG. 1) drives a speed reducer 189 which drives a belt191 and pulley 192 on angle drive 193. The latter drives a chain 194which rotates a sprocket 196 to cross shaft 197. On that shaft is a pairof belt pulleys 198, 198 about which the pair of belts 186, 187 iswrapped. The belts are then trained upward, first about a relativelywide idler 199, then up to a tensioning pulley cluster 201 which ispulled upward by a chain 202 passing over rollers 203 and 204 and downinto a tubular housing 205 containing a weight 256 on the end of thechain. The weight, of course, is adjustable to vary the tension on thedriving belts 186, 187.

From the pulley cluster 201 the drive belts pass down- '7 ward, againaround the idler 199, forward to the idler pulleys 207, 207 carried oncross shaft 208 and thence toward, between, and parallel to the guides181, along the top of the ribbon 161 on guide 179. Now, referring toFIGS. 10 and 11, the belts then follow the first complete wrap of theribbon as it passes around the first mandrel, peel off at the secondwrap, and return to the previously described pulleys 198, 1% to completetheir orbital path. Note that the pairs of drive belts 186, 187 arespaced apart far enough, along the length of the mandrels, to enable thewelding operation to be performed therebetween.

The spacing between drive belts 186, 187 to accommodate ribbons ofdifferent widths is readily varied by changing the spacing between thepairs of pulleys 198, 201 and 20 7.

As best shown in FIG. 10, a pair of hold-down rollers 209 is shown atopthe drive belts, backing them, and maintaining the ribbon 161 inflatwise engagement with the top surface of the guide 179 to direct theribbon onto the first mandrel in a straightline, tangential relation.This provides a beneficial effect in lining up the edges of the ribbonwraps for welding at a point 182.

Another device which has been found helpful in some cases in maintainingalignment of the edges just prior to weldingis a hold-down bar 212,shown in FIGS. 7 and 10. This might serve a dual function as describedin conjunction with FIG. 12.

The use and operation of the apparatus will now be described as it isset up to produce one specific kind and size of spiral tubing, namelycopper tubing having an outside diameter of 1.407" and an insidediameter of 1.375".

In this case, the ribbon or strip 161 would be selected approximately2%" wide and .016" thick. The machine would be set up with a diagonalangle of feed A/F (FIG. 11) at about 37 /2 degrees. The speeds of themandrels as controlled by the adjusting wheels 138 and 146 would beapproximately 20 rpm. for the first mandrel and minus r.p.m. for thesecond mandrel, counterrotating in the directions of the arrows in FIG.11. Under these conditions, finished spiral-welded tubing would come offthe end of the second mandrel at the rate of approximately 2 lineal feetper minute. If desired, an automatic hammer (not shown) may be providedto smooth the spiral welded joint, and a flying saw to cut off thefinished tubing.

The production speed will be limited only by the limitations of thewelding process employed. FIG. 12 shows, in schematic representation, analternate welding method employing radio frequency energy. A radiofrequency transformer secondary 216 is provided with leads to twocontact shoes or brushes 217, 218 contacting the two edges to be weldedslightly in advance of the point of convergence 182a. Current wouldconcentrate along the converging edges and enable welding at very highspeeds. Suitable primary energy means (not shown) would be provided togenerate radio frequency current (200 to 500 kilocycles or more) in thesecondary and in the metal ribbon. The shoe or brush 217 may take theform of the guide bar 212 in order to combine both conductive andhold-down functions.

In the case of the FIG. 12 welding method, it would be possible toreduce the upward inclination of the guide plate 179 which provides theuphill approach to the mandrel assembly, since the weld would becompleted almost instantaneously as the edges converge.

While one form in which the present invention may beembodied has beenshown and described, it will be understood that various modificationsmay be made within the spirit and scope of the invention which should belimited only by the appended claims.

I claim:

1. In apparatus for forming spiral tubing from a ribbon of material,

first and second tubular, rotatable mandrels axially aligned in endwiserelation;

means for guiding and continuously feeding a ribbon of materialdiagonally onto and around said first I and second mandrels insuccession;

means for rotating said first mandrel in one direction which is oppositethe direction of wrap of the ribbon feeding thereon; means for rotatingsaidsecond mandrel opposite said first mandrel; and securing meansintermediate the ends of said mandrels for securing the meeting edges ofsuccessive wraps of said ribbon to produce spiral tubing on said secondmandrel.

2. In apparatus for forming spiral tubing from a ribbon of material, thecombination of claim 1 in which the length of second mandrel infrictional engagement with said ribbon is greater than the length offirst mandrel in frictional engagement with said ribbon, to bias theproduced spiral tubing to rotate in the same direction as the secondmandrel.

3. In apparatus for forming spiral tubing from a ribbon of material, thecombination of claim 1 including mandrel speed control means by whichthe relative speed between the mandrels may be adjusted to vary thepressure between meeting edges of successive wraps at said securingmeans.

4. In apparatus for forming spiral tubing from a ribbon of weldablematerial,

first and second tubular, rotatable mandrels axially aligned in endwiserelation; means for guiding and continuously feeding a ribbon ofweldable material diagonally onto and around said first and secondmandrels in succession;

means for rotating said first mandrel in one direction which is oppositethe direction of wrap of the ribbon feeding thereon;

means for rotating said second mandrel opposite said first mandrel; and

welding means at the juncture between said mandrels for welding themeeting edges of successive wraps of said ribbon to produce spiralwelded tubing on said second mandrel.

5. In apparatus for forming spiral tubing from a ribbon of weldablematerial,

first and second tubular, rotatable mandrels axially aligned and axiallyseparated with a space therebetween;

means for guiding and continuously feeding a ribbon of materialdiagonally onto said first mandrel and in diagonal wraps around saidfirst and second mandrels in succession; means for rotating said firstmandrel in one direction which is opposite the direction of feed of theribbon feeding thereon; 4

means for rotating said second mandrel in a direction opposite saidfirst mandrel; and

welding means at said space between the mandrels for welding the meetingedges of successive wraps of said ribbon to produce spiral tubing onsaid second mandrel.

6. In apparatus for forming spiral tubing from a ribbon of weldablematerial,

first and second tubular, rotatable mandrels axially aligned and axiallyseparated with a space therebetween;

guide and feed means for guiding and feeding a ribbon of materialdiagonally onto said first mandrel and in diagonal abutting wraps aroundsaid first and second mandrels in succession, said guide' and feed meansbeing oriented to make the first wrap substantially complete about thefirst mandrel and meeting the second wrap at a point over said space tosubstantially completely enclose said space;

means for rotating said first mandrel in one direction ribbon ofweldable material,

a mandrelsupport frame;

a pair of tubular, concentric drive shafts journaled for rotationrelative to the frame and to one another;

first; and second tubular mandrels mounted respectively on said shafts,said mandrels being axially aligned in endwise relation;

means for guiding and continuously feeding a ribbon of materialdiagonally onto said first mandrel and in diagonal wraps around saidfirst and second mandrels in succession;

driving mean-s for driving said drive shafts and their respectivemandrels in opposite directions with the first mandrel being driven in adirection which is opposite the direction of feed of the ribbon;

welding means at the juncture between said mandrels for welding themeeting edges of successive Wraps of said ribbon to said second mandrel;

a cooling tube concentric within said second tubular drive shaft,rotatable therewith, and extending into the second mandrel;

rotating coupling means at the outer end of said second shaft coupledrespectively with cooling fluid inlet and outlet ports through a coolingcircuit which includes passages inside and outside of said cooling tubeand the interior of said second mandrel to withdraw heat from the spiralWelded tubing on the second mandrel.

8. In apparatus for forming spiral tubing from a ribbon of material,

a mandrel support frame;

first and second tubular, rotatable mandrels axially aligned in endwiserelation and jour'na-led for rotation with respect to saidsupport frame;

an auxiliary frame;

guide means supported on said auxiliary frame for guiding a ribbon ofmaterial diagonally onto said first mandrel;

feeding means supported on said auxiliary frame for feeding said ribbonalong said guide means and in diagonal wraps around said first andsecond mandrels in succession;

means for driving said mandrels in opposite directions with the firstmandrel being driven in a direction which is opposite the direction ofwrap. of the ribbon;

a ribbon storage reel supported on said auxiliary frame and alignedwith. said guide. means to feed ribbon to the mandrels via the guidemeans;

said mandrel support frame having supported thereon securing meansintermediate the ends of the mandrels for securing the meeting edges ofsuccessive wraps of ribbon to produce spiral tubing on said secondmandrel;

said auxiliary frame being pivoted on the mandrel support frame foradjustment about an axis which extends generally in a direction tointersect an area adjacent the securing means;

whereby the guide means and ribbon storage reel may be pivotallyadjusted about said axis relative to said mandrels to adjust the angleof approach of the ribbon to the mandrels to enable the use of differentproduce spiral welded tubing on- 16 width ribbons and different diametermandrels in producing tubing of preselected size. 9. In apparatus forforming spiral tubing from a ribbon of material, the combination ofclaim 8 in which the ribbon storage reel, the feeding means and theguide means are constructed to accommodate different widths of ribbon.

10. In apparatus for forming spiral tubing from a ribbon of Weldablematerial,

first and second tubular, rotatable mandrels axially aligned in endwiserelation; 7

guide means for guiding a ribbon of material diagonally onto and inwraps around said first and second mandrels in succession;

means for driving said mandrels in opposite directions with the firstmandrel rotating in the direction to oppose the wrap of ribbon;

ribbon feeding means including endless flexible belt means trained formovement in an orbital path 7 along said guide means and parallelthereto and following at least the first ribbon Wrap about the mandrels;said endless flexible belt means having a frictional surface engageablewith the ribbon; means for tensioning the belt means to frictionallyengage the ri bbon as it wraps around said mandrels; drive means formoving said belt means in said orbital path; and

welding means adjacent said mandrels in an area where the meeting edgesof successive wraps of ribbon conform with the mandrels and with oneanother for continuously welding said. meeting edges to produce spiraltubing on said second mandrel.

11. In apparatus for forming spiral tubing from a ribbon of welda-blematerial, the combination of claim 10 including hold-down roller meansbacking said belt means on the exit end portion of the guide means toconstrain said ribbon to approach said first mandrel in a straightlinetangential relation.

. 12. In apparatus for forming spiral tubing from a ribbon of weldablematerial, the combination of claim 10 in which said belt means includes.a pair of belts running along in spaced apart, side-by-side relationshipand means for varying the spacing between said belts toaccommodatewidths of ribbon.

13. In apparatus for forming spiral tubing from a ribbon of weldablematerial, the combination of claim 10 in which successive belt wraps arepositioned over the first and second mandrels respectively and spacedapart sufiiciently, lengthwise. of the mandrels, to provide an area fora continuous welding operation therein, and welding means in said areabetween said belt wraps for continuously welding the meeting edges ofsuccessive ribbon wraps to produce spiral tubing on said second.mandrel. 14-. In apparatus for forming spiral tubing from a ri bon ofmaterial,

first and second tubular, rotatable mandrels axially aligned in endwiserelation; means for guiding and continuously feeding, a ribbon ofmaterial froin a loose loop diagonally onto and around said first andsecond. mandrels in succession; a ribbon storage reel above said loopfrom which ribbon is payed into said loop, means for driving said reelto pay ribbon into said loop, sensing means for sensing a condition ofsaid loop, and control means responsive to said sensing means forautomatically actuating said driving means to pay out ribbon to maintainsaid loop in a predetermined condition; means for rotating said firstmandrel in one direction which is opposite the direction of wrap of theribbon feeding thereon; means for rotating said second mandrel oppositesaid first mandrel; and

means intermediate the ends of mandrels for securing the meeting edgesof successive wraps of said ribbon to produce spiral tubing on saidsecond mandrel.

15. In apparatus for forming spiral tubing from a ribbon of weldablematerial,

first and second tubular, rotatable mandrels axially aligned in endwiserelation;

an elongated guide diagonally approaching said first mandrel to guide aribbon of weldable material diagonally toward said first mandrel;

drive means for said ribbon effective to feed it along said guide anddiagonally onto and in wraps around said first and second mandrels insuccession;

means for rotating said first mandrel in one direction which is oppositethe direction of wrap of the ribbon feeding thereon;

means for rotating said second mandrel opposite said first mandrel;

welding means at the juncture between said mandrels for welding themeeting edges of successive wraps of said ribbon to produce spiralwelded tubing on said second mandrel; and

. said guide means being canted about its length to guide the ribboninto tangenecy with the surface of the first mandrel along a line onsaid surface which is non-parallel to the mandrel and is in advance ofthe welding means.

16. In apparatus for forming spiral tubing from a ribbon of weldablematerial,

first and second tubular, rotatable mandrels axially aligned in endwiserelation; a storage reel for a weldable ribbon rotatable about an axisto pay off ribbon in a plane parallel to said axis;

an. elongated guide coplanar with the reel and havinga ribbon-guidingsurface which is parallel with the axis of the reel;

the reel and the ribbon-guiding surface being in a plane whichintersects the first mandrel diagonally for feeding a ribbon in saidplane from the reel, along the ribbon-guiding surface, and thencediagonally toward said first mandrel without warping or twisting saidribbon;

drive means for said ribbon effective to feed it along said guide anddiagonally onto and in wraps around said first and second mandrels insuccession;

means for rotating said first mandrel in one direction which is oppositethe direction of wrap of the ribbon feeding thereon;

means for rotating said second mandrel opposite said first mandrel;

welding means at the juncture between said mandrels for welding themeeting edges of successive wraps of said ribbon to produce spiralwelded tubing on said second mandrel; and

said guide means being canted about its length to guide the ribbon intotangency with the surface of the first mendrel along a line on saidsurface which is nonparallel to the mandrel and is in advance of thewelding means.

17. In apparatus for forming spiral tubing from a ribbon of weldablematerial, support frame means having: a pair of tubular, horizontal,concentric drive shafts journaled for rotation relative to the frame andto one another;

first and second tubular rotatable, horizontal mandrels mountedrespectively on said shafts, said mandrels being axially aligned inendwise relation with a welding space therebetween;

a reel having a coil of ribbon Wound thereon, a loose loop 'of ribbondepending therefrom, and a ribbon guide, all disposed in an uprightnon-vertical plane diagonally intersecting said first mandrel adjacentsaid welding space;

reel driving means for paying ribbon into said loose loop and effectiveto maintain a predetermined condition of slack in said loop;

said ribbon being trained from said loose loop, along said guide anddiagonally onto and in abutting spiral wraps around said first andsecond mandrels in succession;

ribbon feeding means including: 7

an endless friction belt extending along the ribbon on said guide andaround successive Wraps of ribbon about the first and second mandrels,

driving means for moving said friction belt in an orbital path from saidguide onto said mandrels to feed ribbon in that direction,

said friction belt following said ribbon about said mandrels in a spiralpath with an open area between belt wraps, thereby exposing the meetingedges of the corresponding ribbon wraps at said welding space betweenthe mandrels; first mandrel driving means for rotating the first mandreldrive shaft to rotate said first mandrelin one direction which isopposite the direction of wrap of the ribbon being fed thereon; secondmandrel driving means for rotating the second mandrel drive shaft in adirection to rotate the second mandrel opposite said first mandrel;control means for the mandrel driving means for varying the speed ofeither mandrel independent of the other; welding means at said open areabetween said belt wraps for continuously welding the meeting edges ofsuccessive wraps of ribbon over said welding space :10 produce spiralwelded tubing on said second manrel; means for conducting gas throughsaid drive shafts to said welding space; and means for conductingcooling fluid to and from the second mandrel through said drive shafts.

References Cited by the Examiner UNITED STATES PATENTS 8/1955 Fay 228-173/ 1965 Napieo et al. 22817 8/1966 Groves et al. 228-49

1. IN APPARATUS FOR FORMING SPIRAL TUBING FROM A RIBBON OF MATERIAL,FIRST AND SECOND TUBULAR, ROTATABLE MANDRELS AXIALLY ALIGNED IN ENDWISERELATION; MEANS FOR GUIDING AND CONTINUOUSLY FEEDING A RIBBON OFMATERIAL DIAGONALLY ONTO AND AROUND SAID FIRST AND SECOND MANDRELS INSUCCESSION; MEANS FOR ROTATING SAID FIRST MANDREL IN ONE DIRECTION WHICHIS OPPOSITE THE DIRECTION OF WRAP OF THE RIBBON FEEDING THEREON; MEANSFOR ROTATING SAID SECOND MANDREL OPPOSITE SAID FIRST MANDREL; ANDSECURING MEANS INTERMEDIATE THE ENDS OF SAID MANDRELS FOR SECURING THEMEETING EDGES OF SUCCESSIVE WRAPS OF SAID RIBBON TO PRODUCE SPIRALTUBING ON SAID SECOND MANDREL.